Any geometric sequence can be expressed as:
a(n)=ar^(n-1), a=initial term, r=common ratio, n=term number.
Here we are give the initial term so we have to solve to solve for the common ratio...
a(5)=-1280 and a(1)=-5 so
-1280=-5r^(5-1)
-1280=-5r^4
256=r^4
256^(1/4)=r
4=r, so our sequence is:
a(n)=-5(4^(n-1)), so the 7th term is:
a(7)=-5(4^6)
a(7)= -20480
Answer:
12 nickels and 13 dimes
Step-by-step explanation:
d = # of dimes
n = # of nickels
Set up a System of Equations as follows:
d + n = 25
.10d + .05n = 1.90
now solve for 'd' or 'n' and use Substitution:
d = 25-n
.10(25-n) + .05n = 1.90
2.5 - .10n + .05n = 1.90
-.10n + .05n = -0.6
-.05n = -0.6
n = -0.6/-.05
n = 12
d + 12 = 25
d = 13
Check: 12(.05) + 13(.10) should equal 1.90
0.60 + 1.30 = 1.90
1.90 = 1.90
First you need to rewrite the equation in the form y = mx +b:
2y = x-4
Divide all terms by 2:
2y / 2 = x/2 - 4/2
Simplify:
y = 1/2x - 2
The slope of the line is 1/2.
A perpendicular line has a slope of the negative reciprocal, which would be -2.
Now using the point slope method:
y - y1 = m(x-x1)
Using the given point of (8,-4) and m = -2
you get:
y +4 = -2(x-8)
Simplify:
y +4 = -2x +16
Now subtract 4 from both sides to get the final equation:
y = -2x +12
C? either B or C i believe. Hope this helps